was a town located in Kitauonuma District, Niigata Prefecture, Japan.
As of 2003, the town had an estimated population of 5,549 and a density of 110.91 persons per km<sup>2</sup>. The total area was 50.03 km<sup>2</sup>.
During the 2004 Chà «etsu earthquake, Kawaguchi was the only town to report the maximum value of 7 on the Japan Meteorological Agency seismic intensity scale.
On March 31, 2010, Kawaguchi was merged into the expanded city of Nagaoka.